Vehicles, especially large cargo-carrying vehicles, such as tractor-trailers and buses, operate in a variety of load conditions, ranging from fully loaded, to empty. The horsepower required for moving the vehicle will vary depending on the load conditions. The way a driver operates a vehicle can also impact the fuel economy. For example, by gradually transitioning from a stopped state to a cruising speed, less fuel may be consumed than by rapidly accelerating from a stopped state. However, many drivers feel the pressure of time constraints, and the desire to minimize time spent on a delivery route will often outweigh the desire to maximize fuel economy.
Due to increasing cost of fuel, it is therefore desirable to provide a system that maximizes fuel economy, with minimal dependence on the driving techniques or actions of the vehicle operator. With any fuel economizing solution, it is equally desirable to avoid “over governing” of the engine to the point where driving is difficult or unsafe.
Electronic control modules for managing the operation of internal combustion engines are well known and widely used in the automotive and tractor truck industries. Such modules are typically operable to control engine fueling as well as many other engine and/or vehicle operating conditions. One technique known in the art is the control of the ramp rate, the rate of RPM increase (a.k.a. “ramp up”) of a combustion engine. Ramp rate control is the subject of U.S. Pat. No. 7,121,977 to Markyvech which is incorporated herein by reference, to the extent consistent with the present disclosure. The aforementioned disclosure, while taking steps to address fuel economy, still has various shortcomings, such as high complexity, due to requiring various sensors and/or computer systems for performing vehicle weight estimation. Therefore, what is needed is an improved engine control system having reduced complexity.